Gas furnace



J. ZANDER.

GAS FURNACE.

, mruc'mon FILED MAY 8. 1920. 1,406,713. Patented'Feb. 14, 1922.

3 SHEETS-SHEET I.

J.ZANDE&

GAS FURNACE.

APPLICATION FILED 'MAY 8, I920- 1,406,713. Patented Feb. 14, 1922.

3 SHEETS-SHEET 2.

.l. ZANDER.

GAS FURNACE.

APPLICATION man MAY 3. 1920.

Patented Feb. 14, 1922.

3 SHEETS-SHEET 3.

V rk vs F\ p Q thereof.

UNirEo STAT-ES PATENT OFFICE.

JOHN ZANDER, OF CHICAGO, ILLINOIS.

GAS FURNACE.

Application filed May 8, 1926.

To all whom it may concern Be it known that 1, JOHN ZANDER, a citizen ofthe United States residing at Chicago, in the county of dock and Stateof Illinois, have invented certain new and use ful Improvements in GasFurnaces, of which the following is a specification.

My invention relates to improvements in gas furnaces.

The object of my invention is to provide a furnace of this character,which shall be more efficient than'those used heretofore.-

Contributory objects are to provide an improved furnace in which theincoming air and the gas meet and thoroughly mix just prior to enteringthe heating chamber, the air being preheated by the products ofcombustion; to provide a furnace of this type in which part of theproducts of combustion pass directly to the outlet and the remainderpass over the walls of the preheating passages, the proportion thusemployed for pre heating purposes being under the control of theoperator whereby the temperature of the incoming air may be regulatedaccurately, and to provide a furnace in which a high temperatureismaintained in the heating chamber with a reducing atmosphere, completeoxidization of the fuel taking place after the burning fuel leaves theheating chamber, the heat of this further combustion being used in largepart for preheating purposes and not wasted.

()ther advantages will be apparent from the more detailed description ofthe several embodiments of the invention illustrated in the drawings.

Figure 1 is a top plan view of a brass melting furnace.

Fig. 2 is a central sectional elevation Fig. 3 is a front elevation.

Fig. 4 is a side elevation.

Fig. 5 is a section of a furnace of theopen hearth type.

Fig. 6 is a longitudinal section thereof.

Fig. 7 is a section on the line 7-7 of Fig. 9 of a gas heated forge.

Fig. 8 is a section on the line 88 of Fig. 9.

Fig. 9 is a sectional elevation on the hue 9-9 of Fig. 10. v

h Fig. 10 is a front elevation of, said forge, and

Specification of Letters Patent.

Patented Feb. 14, 1922.

Serial No. 379,778.

Fig. 11 is a section on the line 11ll of Fig. 9.

The first form of furnace illustrated is referred to as a brass furnace,although it may be used for melting various other metals or alloys. Itcomprises a pair of suitable standards 1,1, which support trunnions 2,2, the latter being secured to opposite sides of the furnace shell 8.The furnace is adapted to rock about its trunnions to enable thecontents to be poured. The shell is lined with suitable refractorymaterial f, a melting chamber 5 being provided which is surrounded withthis material. The fuel, which is preferably in the form of gas, isconducted to the furnace through a pipe 6 arranged concentrically at theaxis about which the furnace rocks, the gas flowing through a furtherpipe 7 and being delivered to the heating chamber, as shown in Fig. 2.The air is supplied from any suitable source through pipe 8 passingthrough the opposite trui1- nion and through a further pipe 9, whichdelivers it to a preheater preferably in the form of a casting havingcircular passageways 10 arranged concentrically with reference to thegas pipe 7. This preheater is heated by the products of combustion, ashereinafter described, and the incoming air flows from one circularpassage 10 to the passageway below it, through openings 11 located onopposite sides of the preheater, the air being caused to follow acircuitous course in order to increase its temperature effectively. Theheated air then flows through a port 12 uniting with the gas above themelting chamber. The port 12 is arranged somewhat tangentially withrespect to the circular orifice through which the gas flows so thatthere is a thorough mixing of the two as they enter the combustionchamber.

Thetemperature in the melting chamber 5 is very much higher than thetemperature due to combustion of the gas, by an amount represented bythe initial preheating of the air and hence of the mixture of air andgas prior to combustion. iVith this arrangement a high temperature maybe maintained in the melting chamber, sufficient to melt brass pigs orother metal.

The products of combustion pass out through the outlet 13. The burninggas, as it flows to said outlet, passes one or more orifices 14 throughwhich air may be admitted to complete the combustion. The heat of thisfurther combustion is not wasted, however, as the major portion of theproducts of combustion are caused to flow between and around thecircular passageways 10,.said products of combustion following circularpassageways 15 formed by the walls of the preheater casting. Thepreheater is thus heated to a high temperature, the products ofcombustion, after passing the preheater, being ejected tirough the pipe16. an air pipe 17 being connected thereto to provide an injector actionwhich will draw the products of combustion over the preheater. Asuitable valve 18 is provided (Figs. 1, 3 and 41-) whereby the operatormay vary the effectiveness of the air injector and thereby vary theproportion of the products of combustion, which flows over the preheateras compared with the proportion which flows through the outlet 13.

With the arrangement described, the incoming air may be suitablypreheated with out overheating or destroying the walls of the preheater.The preheated air may be preheated at least 1,000 E, whichcorrespondingly raises the flame temperature. As a result a very hightemperature is attained with a reducing flame.

In prior furnaces where preheating has been attempted, the preheater hasnecessarily been small to avoid overheating and destruction by theproducts of combustion, all of which were caused to flow past thepreheater. In furnaces where no preheater has been employed, theproducts of combustion pass directly to the outlet at practicallyworking temperature, thereby wasting an enormous quantity of heat. Withmy construction I not only provide a very high flame temperature withoutthe disadvantage of an oxidizing atmosphere, but, I also pro vide meansfor utilizing practically all of the heat of combustion of the wastegases.

The furnace is charged through a suitable hinged door 19, the moltenbath being poured from the furnace through a suitable spout 20 which isalso closed during the melting operation by means of a suitable hingedplug or door 21 to prevent the admission of air and loss of heat throughescape of partially burned gases.

The furnace shown in Figs. 5 and 6 is of the reverberatory type. It isprovided with suitable refractory walls 30 and roof 31 and with acentral partition 32 at one end. One of the side walls has an opening 33or charging door. The air is admitted through a pipe 34: to thepreheater 35, which is similar in 'eneral to the preheater previouslydescri ed, the heated air passing out through an outlet 36 at whichpoint it meets the gas which is admitted through the pipe 37. Two suchpreheaters are preferably employed, one located on each side of thecentral partition 32. The gas and heated air mix with a rotary motion inthe manner previously described and become thoroughly mixed as theypassthrough the ports 38 into 7 products of combustion then passdownwardly and to the left, as shown in Fig. 5, and upwardly over thepreheater in the opposite chamber 41 passing out through the pipe 42,the flow being regulated by means of the air injector 43, as previouslydescribed. Adjustable vents 4. 1 are also provided to permit the escapeof such productsof combus tion as are not drawn out by the injector.

The heating furnace illustrated in Fig. 7-11 inclusive is preferably ofthe type used to heat bars or rods preliminary to forging operations.suitable refractory walls 50 enclosing an upper chamber 51 and a lowerchamber 52. Air is admitted'through the pipe 53 and passes back andforth through a series of pipes 54 in the lower chamber, forming thepreheater. The heated air then passes up through the pipe 55 flowingoutwardly through the ducts 56 at which point it meets the incoming gasfrom the two pipes 57. The mixing is effected with a rotary motion aspreviously explained, the combined air and gas issuing from the ports 58into the heating chamber 51. The burning gas flows to the opposite endof the chamber, then down through the vertical passageway 59 to thelower chamber 52, flowing over the preheater 54: and heating the sameand thence through the outlet 60 to the injector 61 and outlet pipe 62.In this case also some of the burning gases escape through the opening63, which is the o ening through whicharc inserted the ro s to beheated. The flame, which issues from the opening 63, heats the incomingas in the pipes 64;. In other words, either the air, the gas or bothmaybe heated. V The removable block 65 permits slag and other foreignmatter to be scraped out of the heating chamber. 7

It will be noted in the first form of device that the preheatersurrounds the burner whereby the products of combustion heat not onlythe-preheater, but also heat the burner as well. 1

Although I have illustrated an air injector for causing the products ofcombustion to flow past the preheater, it is apparent that other meansmay be substituted for this purpose. In the various types of furnacesillustrated the means for causing the products of combustion to divideand flow in two The furnace in this case has separate paths is locatedin the path which includes the preheater. It is evident, however, thatsaid means may be located in the path which leads directly to theoutlet, if desired, or in both paths. Various other changes may be madein the structure illustrated without departing from the invention asexpressed in the appended claims.

What I claim is 1. In a furnace, the combination with a heating chamber,of a fuel supply therefor, an air preheater connecting with said fuelsupply, a direct outlet for the products of combustion from said heatingchamber, and a second outlet in communication with the space surroundingsaid preheater whereby part of the products of combustion pass over saidpreheater to heat the same.

2. In a furnace, the combination with a heating chamber, of a fuelsupply therefor, an air preheater connecting with said fuel supply, adirect outlet for the products of combustion from said heatingchamber,asec- 0nd outlet in communication with the space surroundingsaid preheater whereby part of the products of combustion pass over saidpreheater to heat the same, and means for regulating the flow throughone of said outlets.

3. In a furnace, the combination with a heating chamber, of a fuelsupply connection and an air supply connection, means for admitting airto the burning fuel after it leaves the heating chamber to complete thecombustion, means for drawing the products of combustion over theconnection for the incoming air, and means for regulating the amount ofthe products of combustion thus employed.

4. A heating furnace having a heating chamber, an inlet port therefor, agas pipe communicating with said port, an air preheater alsocommunicating with said port by a tangential connection. to insuremixing of the air and gas, and an air injector arranged to draw theproducts of combustion over said preheater.

5. A heating furnace having a heating chamber, an inlet port therefor, agas pipe communicating with said port, an air preheater alsocommunicating with said port, and an air injector arranged to draw theproducts of combustion over said preheater.

6. A heating furnace having a heating chamber, an inlet port therefor, agas pipe communicating with said port, an air preheater alsocommunicating with said port by a tangential connection to insure mixingof the air and gas, an air injector arranged to draw the products ofcombustion over said preheater, and an additional outlet in directcommunication with said heating chamber through which part of theproducts of combustion pass, the amount being regulated by said airinjector.

7. The combination with a burner, of a preheater arranged concentrictherewith and comprising a series of annular passages for air withannular passages betweenthem for the products of combustion, wherebysaid products of combustion surround and heat said burner.

8. In a heating furnace, a burner having an axially arranged fuel inletand a tangentially arranged air inlet, for mixing said fuel and air.

9. In a furnace, means for admitting fuel and air to the heatingchamber, means for preheating one of said constituents to produce a highflame temperature in said chamber with incomplete combustion, and meansfor admitting additional air to said flame after it leaves said chamberto complete said combustion.

In testimony whereof, I have subscribed my name.

JOHN ZANDER.

